Substrate processing apparatus including heat-shield plate

ABSTRACT

Provided is a substrate processing apparatus. The substrate processing apparatus in which processes with respect to substrates are performed includes a lower chamber having an opened upper side, the lower chamber including a passage allowing the substrates to pass therethrough in a side thereof, an external reaction tube closing the opened upper side of the lower chamber to provide a process space in which the processes are performed, an internal reaction tube disposed within the external reaction tube, the internal reaction tube being disposed around a substrate holder placed in the process position to define a reaction region with respect to the substrates, a heater disposed outside the external reaction tube to heat the process space, the substrate holder on which the one or more substrates are vertically stacked, the substrate holder being movable between a stacking position in which the substrates are stacked within the substrate holder and a process position in which the processes with respect to the substrates are performed, and a heat-shield plate disposed under the substrate holder to close an opened lower side of the internal reaction tube when the substrate holder is disposed at the process position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35U.S.C. § 119 of Korean Patent Application No. 10-2011-0120258, filed onNov. 17, 2011, the entire contents of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

The present invention disclosed herein relates to an apparatus forprocessing a substrate, and more particularly, to a substrate processingapparatus including a heat-shield plate.

Ordinary selective epitaxy processes involve deposition reaction andetching reaction. The deposition and etching reactions may occursimultaneously at slightly different reaction rates with respect to apolycrystalline layer and an epitaxial layer. While an existingpolycrystalline layer and/or an amorphous layer are/is deposited on atleast one second layer during the deposition process, the epitaxiallayer is formed on a surface of a single crystal. However, the depositedpolycrystalline layer is etched faster than the epitaxial layer. Thus,corrosive gas may be changed in concentration to perform a net selectiveprocess, thereby realizing the deposition of an epitaxial material andthe deposition of a limited or unlimited polycrystalline material. Forexample, a selective epitaxy process may be performed to form anepitaxial layer formed of a material containing silicon on a surface ofsingle crystal silicon without leaving the deposits on a spacer.

Generally, the selective epitaxy process has several limitations. Tomaintain selectivity during the selective epitaxy process, a chemicalconcentration and reaction temperature of a precursor should be adjustedand controlled over the deposition process. If an insufficient siliconprecursor is supplied, the etching reaction is activated to decrease thewhole process rate. Also, features of the substrate may be deterioratedwith respect to the etching. If an insufficient corrosive solutionprecursor is supplied, selectivity for forming the single crystallineand polycrystalline materials over the surface of the substrate may bereduced in the deposition reaction. Also, typical selective epitaxyprocesses are performed at a high reaction temperature of about 800° C.,about 1,000° C., or more. Here, the high temperature is unsuited for themanufacturing process due to uncontrolled nitridation reaction andthermal budge on the surface of the substrate.

SUMMARY OF THE INVENTION

The present invention provides a substrate processing apparatus whichprevents heat provided into an internal reaction tube from beingtransmitted into a lower chamber.

The present invention also provides a substrate processing apparatuswhich prevents a reaction gas supplied into an internal reaction tubefrom being deposited on a lower chamber.

Further another object of the present invention will become evident withreference to following detailed descriptions and accompanying drawings.

Embodiments of the present invention provide substrate processingapparatuses in which processes with respect to substrates are performed,the substrate processing apparatuses including: a lower chamber havingan opened upper side, the lower chamber including a passage allowing thesubstrates to pass therethrough in a side thereof; an external reactiontube closing the opened upper side of the lower chamber to provide aprocess space in which the processes are performed; an internal reactiontube disposed within the external reaction tube, the internal reactiontube being disposed around a substrate holder placed in the processposition to define a reaction region with respect to the substrates; aheater disposed outside the external reaction tube to heat the processspace; the substrate holder on which the one or more substrates arevertically stacked, the substrate holder being movable between astacking position in which the substrates are stacked within thesubstrate holder and a process position in which the processes withrespect to the substrates are performed; and a heat-shield platedisposed under the substrate holder to close an opened lower side of theinternal reaction tube when the substrate holder is disposed at theprocess position.

In some embodiments, the substrate processing apparatuses may furtherinclude: at least one supply nozzle disposed along an inner wall of theexternal reaction tube, the at least one supply nozzle having a supplyhole for discharging the reaction gas; and at least one exhaust nozzledisposed along the inner wall of the external reaction tube, the atleast one exhaust nozzle having an exhaust hole for suctioning anon-reaction gas and byproducts within the process space.

In other embodiments, the substrate holder may be disposed within thestacking space at the stacking position and disposed within the processspace at the process position.

In still other embodiments, the substrate processing apparatuses mayfurther include a rotation shaft connected to the substrate holder, therotation shaft being rotated in a preset direction during the processes,wherein the heat-shield plate is disposed on the rotation shaft.

In even other embodiments, the heat-shield plate may be formed of one ofceramic, quartz, a metal material coated with ceramic, AlN, Ni, andINCONEL® (i.e. Ni—Cr alloy).

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the present invention, and are incorporated in andconstitute a part of this specification. The drawings illustrateexemplary embodiments of the present invention and, together with thedescription, serve to explain principles of the present invention. Inthe drawings:

FIG. 1 is a schematic view of a semiconductor manufacturing equipmentaccording to an embodiment of the present invention;

FIG. 2 is a view of a substrate processed according to an embodiment ofthe present invention;

FIG. 3 is a flowchart illustrating a process for forming an epitaxiallayer according to an embodiment of the present invention;

FIG. 4 is a schematic view illustrating an epitaxial apparatus of FIG.1;

FIG. 5 is a cross-sectional view illustrating a lower chamber and asubstrate holder of FIG. 1;

FIG. 6 is a schematic cross-sectional view illustrating an externalreaction tube, an internal reaction tube, supply nozzles, and exhaustnozzles of FIG. 1;

FIG. 7 is a view illustrating a state in which a side heater and anupper heater of FIG. 1 are removed;

FIG. 8 is a cross-sectional view illustrating arrangements of the supplynozzles and thermocouples of FIG. 1;

FIG. 9 is a cross-sectional view illustrating arrangements of theexhaust nozzles and the thermocouples of FIG. 1;

FIG. 10 is a view of supply lines respectively connected to supplynozzles of FIG. 1;

FIG. 11 is a view illustrating a flow of a reaction gas within theinternal reaction tube of FIG. 1;

FIGS. 12 to 14 are views illustrating an exhaust process using anexhaust port and an auxiliary exhaust port; and

FIGS. 15 and 16 are views illustrating a state in which the substrateholder of FIG. 1 is moved into a process position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to FIGS. 1 to 16. The presentinvention may, however, be embodied in different forms and should not beconstructed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the present inventionto those skilled in the art. In the drawings, the shapes of componentsare exaggerated for clarity of illustration.

FIG. 1 is a schematic view of a semiconductor manufacturing equipment 1according to an embodiment of the present invention. The semiconductormanufacturing equipment 1 includes process equipment 2, an equipmentfront end module (EFEM) 3, and an interface wall 4. The EFEM 3 ismounted on a front side of the process equipment 2 to transfer a wafer Wbetween a container (not shown) in which substrates S are received andthe process equipment 2.

The EFEM 3 includes a plurality of loadports 60 and a frame 50. Theframe 50 is disposed between the loadports 60 and the process equipment2. The container in which the substrate S is received is placed on theloadports by a transfer unit (not shown) such as an overhead transfer,an overhead conveyor, or an automatic guided vehicle.

An airtight container such as a front open unified pod (FOUP) may beused as the container. A frame robot 70 for transferring the substrate Sbetween the container placed on the loadports 60 and the processequipment 2 is disposed within the frame 50. A door opener (not shown)for automatically opening or closing a door of the container may bedisposed within the frame 50. Also, a fan filter unit (FFU) (not shown)for supplying clean air into the frame 50 may be provided within theframe 50 so that the clean air flows downward from an upper side withinthe frame 50.

Predetermined processes with respect to the substrate S are performedwithin the process equipment 2. The process equipment 2 includes atransfer chamber 102, a loadlock chamber 106, cleaning chambers 108 aand 108 b, a buffer chamber 110, and epitaxial chambers (or epitaxialapparatuses) 112 a, 112 b, and 112 c. The transfer chamber 102 may havea substantially polygonal shape when viewed from an upper side. Theloadlock chamber 106, the cleaning chambers 108 a and 108 b, the bufferchamber 110, and the epitaxial chambers 112 a, 112 b, and 112 c aredisposed on a side surface of the transfer chamber 102.

The loadlock chamber 106 is disposed on a side surface adjacent to theEFEM 3 among side surfaces of the transfer chamber 102. The substrate Sis loaded to the process equipment 2 after the substrate S istemporarily stayed within the loadlock chamber 106 so as to perform theprocesses. After the processes are completed, the substrate S isunloaded from the process equipment 2 and then is temporarily stayedwithin the loadlock chamber 106. The transfer chamber 102, the cleaningchambers 108 a and 108 b, the buffer chamber 110, and the epitaxialchambers 112 a, 112 b, and 112 c are maintained in a vacuum state. Theloadlock chamber 106 is switched from the vacuum state into anatmospheric state. The loadlock chamber 106 prevents externalcontaminants from being introduced into the transfer chamber 102, thecleaning chambers 108 a and 108 b, the buffer chamber 110, and theepitaxial chambers 112 a, 112 b, and 112 c. Also, since the substrate Sis not exposed to the atmosphere during the transfer of the substrate S,it may prevent an oxide layer from being grown on the substrate S.

Gate valves (not shown) are disposed between the loadlock chamber 106and the transfer chamber 102 and between the loadlock chamber 106 andthe EFEM 3. When the substrate S is transferred between the EFEM 3 andthe loadlock chamber 106, the gate valve disposed between the loadlockchamber 106 and the transfer chamber 102 is closed. Also, when thesubstrate S is transferred between the loadlock chamber 106 and thetransfer chamber 102, the gate valve disposed between the loadlockchamber 106 and the EFEM 3 is closed.

A substrate handler 104 is disposed in the transfer chamber 102. Thesubstrate handler 104 transfers the substrate S between the loadlockchamber 106, the cleaning chamber 108 a and 108 b, the buffer chamber110, and the epitaxial chambers 112 a, 112 b, and 112 c. The transferchamber 102 is sealed so that the transfer chamber 102 is maintained inthe vacuum state when the substrate S is transferred. The maintenance ofthe vacuum state is for preventing the substrate S from being exposed tocontaminants (e.g., O₂, particle materials, and the like).

The epitaxial chambers 112 a, 112 b, and 112 c are provided to form anepitaxial layer on the substrate S. In the current embodiment, threeepitaxial chambers 112 a, 112 b, and 112 c are provided. Since it takesa relatively long time to perform an epitaxial process when compared tothat of a cleaning process, manufacturing yield may be improved throughthe plurality of epitaxial chambers. Unlike the current embodiment, fouror more epitaxial chambers or two or less epitaxial chambers may beprovided.

The cleaning chambers 108 a and 108 b are configured to clean thesubstrate S before the epitaxial process is performed on the substrate Swithin the epitaxial chambers 112 a, 112 b, and 112 c. To successfullyperform the epitaxial process, an amount of oxide remaining on thecrystalline substrate should be minimized. If an oxygen content on asurface of the substrate S is too high, oxygen atoms may interruptcrystallographic disposition of materials to be deposited on a seedsubstrate, and thus, it may have a bad influence on the epitaxialprocess. For example, when a silicon epitaxial deposition is performed,excessive oxygen on the crystalline substrate may displace a siliconatom from its epitaxial position by oxygen atom clusters in atom units.The local atom displacement may cause errors in follow-up atomarrangement when a layer is more thickly grown. This phenomenon may beso-called stacking faults or hillock defects. Oxygenation on the surfaceof the substrate may, for example, occur when the substrate is exposedto the atmosphere while the substrate is transferred. Thus, the cleaningprocess for removing a native oxide (or a surface oxide) formed on thesubstrate S may be performed within the cleaning chambers 108 a and 108b.

The cleaning process may be a dry etching process using hydrogen (H*)and NF3 gases having a radical state. For example, when the siliconoxide formed on the surface of the substrate is etched, the substrate isdisposed within a chamber, and then, the chamber has a vacuum atmospheretherein to generate an intermediate product reacting with the siliconoxide within the chamber.

For example, when reaction gases such as a hydrogen radical gas (H*) anda fluoride gas (for example, nitrogen fluoride (NF₃)) are supplied intothe chamber, the reaction gases are reduced as expressed in thefollowing reaction formula (1) to generate an intermediate product suchas NH_(x)F_(y) (where x and y are certain integers).H*+NF₃

NH_(x)F_(y)  (1)

Since the intermediate product has high reactivity with silicon oxide(SiO₂), when the intermediate product reaches a surface of the siliconsubstrate, the intermediate product selectively reacts with the siliconoxide to generate a reaction product ((NH₄)₂SiF₆) as expressed infollowing reaction formula (2).NH_(x)F_(y)+SiO₂

(NH₄)₂SiF₆+H₂O  (2)

Thereafter, when the silicon substrate is heated at a temperature ofabout 100° C. or more, the reaction product is pyrolyzed as expressed infollowing reaction formula (3) to form a pyrolyzed gas, and then, thepyrolyzed gas is evaporated. As a result, the silicon oxide may beremoved from the surface of the substrate. As shown in the followingreaction formula (3), the pyrolysis gas includes a gas containingfluorine such as an HF gas or a SiF₄ gas.(NH₄)₂SiF₆

NH₃+HF+SiF₄  (3)

As described above, the cleaning process may include a reaction processfor generating the reaction product and a heating process for pyrolyzingthe reaction product. The reaction process and the heating process maybe performed at the same time within the cleaning chambers 108 a and 108b. Alternatively, the reaction process may be performed within one ofthe cleaning chambers 108 a and 108 b, and the heating process may beperformed within the other one of the cleaning chambers 108 a and 108 b.

The buffer chamber 110 provides a space in which the substrate S, onwhich the cleaning process is completed, is stacked and a space in whichthe substrate S, on which the epitaxial process is performed, isstacked. When the cleaning process is completed, the substrate S istransferred into the buffer chamber 110 and then stacked within thebuffer chamber 110 before the substrate S is transferred into theepitaxial chambers 112 a, 112 b, and 112 c. The epitaxial chambers 112a, 112 b, and 112 c may be batch type chambers in which a single processis performed on a plurality of substrates. When the epitaxial process iscompleted within the epitaxial chambers 112 a, 112 b, and 112 c,substrates S on which the epitaxial process is performed aresuccessively stacked within the buffer chamber 110. Also, substrates Son which the cleaning process is completed are successively stackedwithin the epitaxial chambers 112 a, 112 b, and 112 c. Here, thesubstrates S may be vertically stacked within the buffer chamber 110.

FIG. 2 is a view of a substrate processed according to an embodiment ofthe present invention. As described above, the cleaning process isperformed on the substrate S within the cleaning chambers 108 a and 108b before the epitaxial process is performed on the substrate S. Thus, anoxide 72 formed on a surface of a substrate 70 may be removed throughthe cleaning process. The oxide may be removed through the cleaningprocess within the cleaning chamber 108 a and 108 b. Also, an epitaxysurface 74 formed on the surface of the substrate 70 may be exposedthrough the cleaning process to assist the growth of an epitaxial layer.

Thereafter, an epitaxial process is performed on the substrate 70 withinthe epitaxial chambers 112 a, 112 b, and 112 c. The epitaxial processmay be performed by chemical vapor deposition. The epitaxial process maybe performed to form an epitaxy layer 76 on the epitaxy surface 74. Theepitaxy surface 74 formed on the substrate 70 may be exposed by reactiongases including a silicon gas (e.g., SiCl₄, SiHCl₃, SiH₂Cl₂, SiH₃Cl,Si₂H₆, or SiH₄) and a carrier gas (e.g., N₂ and/or H₂). Also, when theepitaxy layer 76 is required to include a dopant, a silicon-containinggas may include a dopant-containing gas (e.g., AsH3, PH₃, and/or B₂H₆).

FIG. 3 is a flowchart illustrating a process for forming an epitaxiallayer according to an embodiment of the present invention. In operationS10, a process for forming an epitaxial layer starts. In operation S20,a substrate S is transferred into cleaning chambers 108 a and 108 bbefore an epitaxial process is performed on the substrate S. Here, asubstrate handler 104 transfers the substrate S into the cleaningchambers 108 a and 108 b. The substrate S is transferred through atransfer chamber 102 in which a vacuum state is maintained. In operationS30, a cleaning process is performed on the substrate S. As describedabove, the cleaning process includes a reaction process for generating areaction product and a heating process for pyrolyzing the reactionproduct. The reaction process and the heating process may be performedat the same time within the cleaning chambers 108 a and 108 b.Alternatively, the reaction process may be performed within one of thecleaning chambers 108 a and 108 b, and the heating process may beperformed within the other one of the cleaning chambers 108 a and 108 b.

In operation S40, the substrate S on which the cleaning process iscompleted is transferred into a buffer chamber 110 and is stacked withinthe buffer chamber 110. Then, the substrate S is on standby within thebuffer chamber 110 so as to perform the epitaxial process. In operationS50, the substrate S is transferred into epitaxial chambers 112 a, 112b, and 112 c. The transfer of the substrate S is performed through thetransfer chamber 102 in which the vacuum state is maintained. Inoperation S60, an epitaxial layer may be formed on the substrate S. Inoperation S70, the substrate S is transferred again into the bufferchamber 110 and is stacked within the buffer chamber 110. Thereafter, inoperation S80, the process for forming the epitaxial layer is ended.

FIG. 4 is a schematic view illustrating the epitaxial apparatus ofFIG. 1. FIG. 5 is a cross-sectional view illustrating the lower chamberand the substrate holder of FIG. 1. An epitaxial apparatus (or anepitaxial chamber) includes a lower chamber 312 b having an opened upperside. The lower chamber 312 b is connected to a transfer chamber 102.The lower chamber 312 b has a passage 319 connected to the transferchamber 102. A substrate S may be loaded from the transfer chamber 102into the lower chamber through the passage 319. A gate valve (not shown)may be disposed outside the passage 319. The passage 319 may be openedor closed by the gate valve.

The epitaxial apparatus includes a substrate holder 328 on which aplurality of substrates S are stacked. The substrates S are verticallystacked on the substrate holder 328. For example, fifteen substrates Smay be stacked on the substrate holder 328. When the substrate holder328 is disposed in a stacking space (or at a “stacking position)provided within the lower chamber 312 b, the substrates S may be stackedwithin the substrate holder 328. As described below, the substrateholder 328 may be elevated. When the substrates S are stacked into aslot of the substrate holder 328, the substrate holder 328 may beelevated so that substrates S are stacked into the next slot of thesubstrate holder 328. When all the substrates are stacked on thesubstrate holder 328, the substrate holder 328 is moved into an externalreaction tube 312 a (or to a “process position”), an epitaxial processis performed within the external reaction tube 312 a.

A heat-shield plate 316 is disposed under the substrate holder 328 andelevated together with the substrate holder 328. When the substrateholder 328 is moved in position to the process position, as shown inFIG. 11, the heat-shield plate 316 closes an opened lower portion of theinternal reaction tube 314. The heat-shield plate 316 may be formed ofone of ceramic, quartz, a metal material coated with ceramic, AlN, Ni,and INCONEL® (i.e. Ni—Cr alloy). The heat-shield plate 316 prevents heatwithin a reaction region from being transmitted into the stacking spacewhen processes are performed. A portion of a reaction gas supplied intothe reaction region may be moved into the stacking space through theopened lower side of the internal reaction tube 314. Here, when thestacking space has a temperature greater than a predeterminedtemperature, a portion of the reaction gas may be deposited on an innerwall of the stacking space. Thus, it may be necessary to prevent thestacking space from being heated due to the heat-shield plate 316.Therefore, it may prevent the reaction gas from being deposited on theinner wall of the stacking space.

Also, to perform a normal epitaxial process in the reaction region ofthe internal reaction tube 314, external obstruction factors should beremoved. However, as described above, since the internal reaction tube314 has the opened lower side, heat within the reaction region may belost through the lower side of the internal reaction tube 314. Here, theheat loss may be fatal to the epitaxial process. The heat-shield plate316 closes the opened lower side of the internal reaction tube 314 toshield heat and prevent heat from being lost.

A lower chamber 312 b includes an exhaust port 344, an auxiliary exhaustport 328 a, and an auxiliary gas supply port 362. The exhaust port 344has a “

” shape. An exhaust nozzle unit 334 that will be described later areconnected to a first exhaust line 342 through the exhaust port 344. Theauxiliary exhaust port 328 a is connected to the auxiliary exhaust line328 b. A gas within the stacking space of the lower chamber 312 b may beexhausted the auxiliary exhaust port 328 a.

The auxiliary gas supply port 362 is connected to a auxiliary gas supplyline (not shown) to supply a gas supplied through the auxiliary gassupply line into the stacking space. For example, an inert gas may besupplied into the stacking space through the auxiliary gas supply port362. As the inert gas is supplied into the stacking space, it mayprevent the reaction gas supplied into the process space from beingintroduced into the stacking space.

Furthermore, since the inert gas is continuously supplied into thestacking space and exhausted through the auxiliary exhaust port 328 a,it may prevent the reaction gas supplied into the process space frombeing moved into the stacking space. Here, the stacking space may be setso that an internal pressure thereof is slightly greater than that ofthe process space. When the stacking pace has a pressure slightlygreater than that of the process space, the reaction gas within theprocess space is not moved into the stacking space.

FIG. 6 is a schematic cross-sectional view illustrating the externalreaction tube, the internal reaction tube, supply nozzles, and theexhaust nozzles of FIG. 1. The external reaction tube 312 a closes anopened upper side of the lower chamber 312 b to provide the processspace in which the epitaxial process is performed. A support flange 442is disposed between the lower chamber 312 b and the external reactiontube 312 a. The external reaction tube 312 is disposed on the supportflange 442. The stacking space of the lower chamber 312 b communicateswith the process space of the external reaction tube 312 a through anopening defined in a center of the support flange 442. As describedabove, when all the substrates are stacked on the substrate holder 328,the substrate holder 328 may be moved into the process space of theexternal reaction tube 312 a.

The internal reaction tube 314 is disposed inside the external reactiontube 312 a to provide a reaction region with respect to a substrate S.The inside of the external reaction tube 312 a is divided into areaction region and a non-reaction region by the internal reaction tube314. The reaction region is defined inside the internal reaction tube314, and the non-reaction region is defined outside the internalreaction tube 314. When the substrate holder 328 is moved to the processposition, the substrate holder 328 is disposed in the reaction region.The reaction region has a volume less than that of the process space.Thus, when the reaction gas is supplied into the reaction region, ausage amount of the reaction gas may be minimized. Also, the reactiongas may be concentrated onto the substrates S stacked within thesubstrate holder 328. The internal reaction tube 314 has a closed upperside and an opened lower side. Thus, the substrate holder 328 is movedinto the reaction region through the lower side of the internal reactiontube 314.

As shown in FIG. 4, a side heater 324 and an upper heater 326 aredisposed to surround the external reaction tube 312 a. The side heater324 and the upper heater 326 heat the process space within the externalreaction tube 312 a. Thus, the reaction space (or the reaction region)may reach a temperature enough to perform the epitaxial process. Theside heater 324 and the upper heater 326 are connected to an upperelevation rod 337 through a support frame 327. When the upper elevationrod 337 is rotated by an elevation motor 338, the support frame 327 maybe elevated.

FIG. 7 is a view illustrating a state in which the side heater 324 andthe upper heater 326 of FIG. 1 are removed. Referring to FIG. 7, thesupport fame 327 may be elevated to remove the side heater 324 and theupper heater 326 from the external reaction tube 312 a. Thus, a workermay more easily maintain and repair the inside of the external reactiontube 312 a and the inside of the lower chamber 312 b.

The epitaxial apparatus further includes a gas supply unit. The gassupply unit includes a supply nozzle unit 332 and an exhaust nozzle unit334. The supply nozzle unit 332 includes a plurality of supply tubes 332a and a plurality of supply nozzles 332 b. The supply nozzles 332 b areconnected to the supply tubes 332 a, respectively. Each of the supplynozzles 332 b has a circular tube shape. A supply hole 332 c is definedin a front end of each of the supply nozzles 332 b. The reaction gas isdischarged through the supply hole 332 c. The supply hole 332 c has acircular sectional area. As shown in FIG. 7, the supply holes 332 c ofthe supply nozzles 332 b may be defined at heights different from eachother.

The supply tubes 332 a and the supply nozzles 332 b are disposed insidethe external reaction tube 312 a. The supply tubes 332 a extendvertically. The supply nozzles 332 b may be disposed substantiallyperpendicular to the supply tubes 332 a. The supply holes 332 c aredefined inside the internal reaction tube 314. Thus, the reaction gasdischarged through the supply holes 332 c may be concentrated into thereaction region within the internal reaction tube 314. The internalreaction tube 314 has a plurality of through-holes 374. The supply holes332 c of the supply nozzles 332 b may be defined inside the internalreaction tube 314 through the through-holes 374.

FIG. 8 is a cross-sectional view illustrating arrangements of the supplynozzles and thermocouples of FIG. 1. Referring to FIG. 8, the supplynozzles 332 b have circular supply holes 332 c, respectively. The supplyholes 332 c of the supply nozzles 332 b are defined in a circumferencedirection along an inner wall of the internal reaction tube 314. Also,the supply holes 332 c are defined in heights different from each other.When the substrate holder 328 is moved into the process position, thesupply nozzles 332 b spray the reaction gas onto each of the substratesS placed on the substrate holder 328. Here, the supply holes 332 c aredisposed at height substantially equal to those of the substrates S,respectively. As shown in FIG. 6, the supply nozzles 332 b are connectedto reaction gas sources (not shown) through the supply lines 372disposed in the support flange 442, respectively.

Each of reaction gas sources may supply a deposition gas (a silicon gas(e.g., SiCl₄, SiHCl₃, SiH₂Cl₂, SiH₃Cl, Si₂H₆, or SiH₄)), a carrier gas(e.g., N₂ and/or H₂), or an etching gas. A selective epitaxy processinvolves deposition reaction and etching reaction. Although not shown inthe current embodiment, when an epitaxy layer is required to include adopant, a dopant-containing gas (e.g., arsine (AsH₃), phosphine (PH₃),and/or diborane (B₂H₆)) may be supplied. Also, in case of a cleaning oretching process, hydrogen chloride (HCl) may be supplied.

As shown in FIG. 6, the exhaust nozzle unit 334 includes a plurality ofexhaust tubes 334 a and a plurality of exhaust nozzles 334 b. Theexhaust nozzles 334 b are connected to the exhaust tubes 334 a,respectively. An exhaust hole 334 c is defined in a front end of each ofthe exhaust nozzles 334 b to suction a non-reaction gas and byproducts.The exhaust hole 334 c has a sectional area having a slot shape. Asshown in FIG. 6, the exhaust nozzles 334 b may be disposed at heightsdifferent from those of the exhaust holes 334 c.

The exhaust tubes 334 a and the exhaust nozzles 334 b are disposedinside the external reaction tube 312 a. The exhaust tubes 334 a extendvertically. The exhaust nozzles 334 b may be disposed substantiallyperpendicular to the exhaust tubes 334 a. The exhaust holes 334 c aredefined inside the internal reaction tube 314. Thus, the non-reactiongas and byproducts may be effectively suctioned from the reaction regionwithin the internal reaction tube 314 through the exhaust holes 334 c.The internal reaction tube 314 has a plurality of through-holes 376. Theexhaust holes 334 c of the exhaust nozzles 334 b may be defined insidethe internal reaction tube 314 through the through-holes 376.

FIG. 9 is a cross-sectional view illustrating arrangements of theexhaust nozzles and the thermocouples of FIG. 1. Referring to FIG. 9,the exhaust nozzles 334 b have exhaust holes 334 c, each having aslot-shaped sectional area, respectively. The exhaust holes 334 c of theexhaust nozzles 334 b are defined in a circumference direction along theinner wall of the internal reaction tube 314. Also, the exhaust holes334 c are defined at heights different from each other. The substrateholder 328 is moved into the process position, the supply nozzles 332 bspray the reaction gas onto each of the substrates S placed on thesubstrate holder 328. Here, the non-reaction gas and byproducts may begenerated within the internal reaction tube 314. The exhaust nozzles 334b suction the non-reaction gas and the byproducts to discharge thenon-reaction gas and the byproducts to the outside. The exhaust holes334 c are defined at heights substantially equal to those of thesubstrates S, respectively. As shown in FIG. 4, the exhaust nozzles 334b are connected to the first exhaust line 342 through the exhaust port344 disposed in the lower chamber 312 b to discharge the non-reactiongas and the byproducts through the first exhaust line 342. The switchingvalve 346 is disposed on the first exhaust line 342 to open or close thefirst exhaust line 342. The turbo pump 348 is disposed on the firstexhaust line 342 to forcibly discharge the non-reaction gas and thebyproducts through the first exhaust line 342. The first exhaust line342 is connected to the second exhaust line 352 to discharge thenon-reaction gas and the byproducts, which are moved along the firstexhaust line 342, through the second exhaust line 352.

The auxiliary exhaust port 328 a is disposed in the lower chamber 312 b.The auxiliary exhaust line 328 b is connected to the auxiliary exhaustport 328 a. The auxiliary exhaust line 328 b is connected to the secondexhaust line 352. The first and second auxiliary valves 328 c and 328 dare disposed on the auxiliary exhaust line 328 b to open or close theauxiliary exhaust line 328 b. The auxiliary exhaust line 328 b isconnected to the first exhaust line 342 through a connection line 343. Aconnection valve 343 a is disposed on the connection line 343 to open orclose the connection line 343.

As shown in FIGS. 8 and 9, thermocouples 382 and 384 are disposedbetween the external reaction tube 312 a and the internal reaction tube314. The thermocouples 382 and 384 are vertically disposed to measuretemperatures according to heights. Thus, a worker may grasp temperatureswithin the process space according to the heights. As a result, effectsof temperature distribution on the process may be previously checked.

FIG. 10 is a view of the supply lines respectively connected to thesupply nozzles of FIG. 1. As shown in FIG. 10, the supply nozzles 332are connected to the reaction gas sources (not shown) through theseparate supply lines 372. Thus, the reaction gas may be uniformlysupplied into the reaction region of the internal reaction tube 314through the plurality of supply nozzles 332. If one supply line 372 isconnected to a plurality of supply nozzles 332, the reaction gas may besupplied with different flow rates according to the supply nozzles 332.Thus, a process rate may vary according to the positions of thesubstrate holder 328.

FIG. 11 is a view illustrating a flow of the reaction gas within theinternal reaction tube of FIG. 1. As described above, the supply holes332 c of the supply nozzles 332 b are defined in the circumferencedirection along the inner wall of the internal reaction tube 314. Also,the supply holes 332 c are defined at height different from each other.Also, the exhaust holes 334 c of the exhaust nozzles 334 b are definedin the circumference direction along the inner wall of the internalreaction tube 314. Also, the exhaust holes 334 c are defined at heightsdifferent from each other. Here, a center of each of the supply holes332 c is symmetric to that of each of the exhaust holes 334 c withrespect to the same height. That is, the supply hole 332 c of the supplynozzle 332 b and the exhaust hole 334 c of the exhaust nozzle 334 b aredisposed opposite to each other with respect to a center of thesubstrate S stacked on the substrate holder 328. Thus, the reaction gassprayed from the supply nozzle 332 b flows toward the exhaust nozzle 334b disposed opposite to the supply nozzle 332 b (indicated as an arrow).Thus, it may secure a sufficient time for which the reaction gas and thesubstrate S react with each other. Here, the non-reaction gas and thebyproducts generated during the process are suctioned and dischargedthrough the exhaust nozzle 334 b.

As shown in FIG. 11, a flow of the reaction gas may vary according to aheight of the substrates S stacked on the substrate holder 328. Thus,the flow of the reaction gas has a phase difference according to aheight of the substrate S. That is, a position of the supply hole 332 cof the supply nozzle 332 b and a position of the exhaust hole 334 c ofthe exhaust nozzle 334 b have a phase difference according to the heightof the substrate S. Referring to FIG. 10, a reference numeral {circlearound (1)} denotes a flow of a reaction gas flowing from the supplynozzle 332 b toward the exhaust nozzle 334 b, and a reference numeral{circle around (2)} denotes a flow of a reaction gas flowing from thesupply nozzle 332 b toward the exhaust nozzle 334 b. The referencenumerals {circle around (1)} and {circle around (2)} have a phasedifference of a predetermined angle. Thus, the reaction gas sprayed fromthe supply hole may be diffused by the reaction gas sprayed from thesupply hole defined at a different height. That is, the flows of thereaction gas having the phase difference may interfere with each other.Thus, the reaction gas may be moved toward the exhaust nozzle 334 b in astate where the reaction gas is diffused by the interference.

Also, the supply hole 332 c of the supply nozzle 332 b has a circularshape. On the other hand, the exhaust hole 334 c of the exhaust nozzle334 b has a slot shape. Thus, the reaction gas sprayed from the supplyhole 332 c of the supply nozzle 332 b may be diffused to have apredetermined width according to a shape of the exhaust hole 334 c (seeFIG. 10). Therefore, an area on which the reaction gas contacts asurface of the substrate S may be increased. Also, the sufficientreaction may be induced to restrict the generation of the non-reactiongas. The reaction gas laminar-flows on the substrate S from the supplyhole 332 c up to the exhaust hole 334 c.

FIGS. 12 to 14 are views illustrating an exhaust process using anexhaust port and an auxiliary exhaust port. As shown in FIG. 4, theexhaust nozzles 334 b are connected to the first exhaust line 342through the exhaust port 344 disposed in the lower chamber 312 b todischarge the non-reaction gas and the byproducts through the firstexhaust line 342. The switching valve 346 is disposed on the firstexhaust line 342 to open or close the first exhaust line 342. The turbopump 348 is disposed on the first exhaust line 342 to forcibly dischargethe non-reaction gas and the byproducts through the first exhaust line342. The first exhaust line 342 is connected to the second exhaust line352 to discharge the non-reaction gas and the byproducts, which aremoved along the first exhaust line 342, through the second exhaust line352.

The auxiliary exhaust port 328 a is disposed in the lower chamber 312 b.The auxiliary exhaust line 328 b is connected to the auxiliary exhaustport 328 a. The auxiliary exhaust line 328 b is connected to the secondexhaust line 352. The first and second auxiliary valves 328 c and 328 dare disposed on the auxiliary exhaust line 328 b to open or close theauxiliary exhaust line 328 b. The auxiliary exhaust line 328 b isconnected to the first exhaust line 342 through a connection line 343. Aconnection valve 343 a is disposed on the connection line 343 to open orclose the connection line 343.

The auxiliary exhaust port 328 a will be described in detail below.First, before a process is performed, the inside of the lower chamber312 b and the inside of the external reaction tube 312 a (or theinternal reaction tube 314) should be in vacuum state. Here, the workermay the inner vacuum states of the lower chamber 312 b and the externalreaction tube 312 a (or the internal reaction tube 314) using theauxiliary exhaust port 328 a. The worker may close the connection valve343 a and the switching valve 346 in a state where the first and secondauxiliary valves 328 c. In this case, a gas may be exhausted through theauxiliary exhaust line 328 b and the second exhaust line 352.

Next, when the gas and the byproducts are exhausted through theauxiliary exhaust line 328 b and the second exhaust line 352 for apredetermined time, the worker may close the second auxiliary valve 328d in a state where the first auxiliary valve 328 c, the connection valve343 a, and the switching valve 346. In this case, the exhaust processmay be performed through the auxiliary exhaust line 328 b, theconnection line 343, the first exhaust line 342, and the second exhaustline 352. Here, the exhaust process may be performed through the turbopump 348. The turbo pump 348 may change an inner pressure of each of thelower chamber 312 b and the external reaction tube 312 a (or theinternal reaction tube 314) into a process pressure using the turbo pump348.

When the insides of the lower chamber 312 b and the external reactiontube 312 a (or the internal reaction tube 314) become in the vacuumstate through above-described two stages, it may prevent an excessivepressure from being applied to the lower chamber 312 b and the externalreaction tube 312 a (or the internal reaction tube 314) due to thehigh-performance turbo pump 348. Also, in a case where the vacuum isformed using the auxiliary exhaust port 328 a directly connected to thelower chamber 312 b, the vacuum may be effectively formed when comparedto a case in which the vacuum is formed using the exhaust port 344connected to the exhaust nozzles 334.

During the process, the worker may close the connection valve 343 a in astate where the first and second auxiliary valves 328 c and 328 d andthe switching valve 346 are opened. In this case, the non-reaction gasand the byproducts suctioned through the exhaust nozzles 334 may bedischarged through the first and second exhaust lines 342 and 352. Also,the inert gas may be supplied into the stacking space of the lowerchamber 312 b through the auxiliary gas supply port 362. In addition,the inert gas within the stacking space of the lower chamber 312 b maybe discharged to the outside through the auxiliary exhaust line 328 b.The stacking space may be set to a pressure slightly greater than thatof the process space. Also, it may prevent the reaction gas within theprocess space from being moved into the stacking space.

As shown in FIG. 4, the substrate holder 328 is connected to therotation shaft 318. The rotation shaft 318 passes through the lowerchamber 312 b and is connected to an elevation motor 319 a and arotation motor 319 b. The rotation motor 319 b is disposed on s motorhousing 319 c. The rotation motor 319 b drives the rotation shaft 318while the epitaxial process is performed to rotate the substrate holder328 (and the substrates S) together with the rotation shaft 318. This isdone because the reaction gas flows from the supply hole 332 c towardthe exhaust hole 334 c, and the reaction gas is reduced in concentrationas the reaction gas is deposited on the substrate S from the supply hole332 c toward the exhaust hole 334 c. To prevent the above-describedphenomenon from occurring, the substrate S may be rotated so that thereaction gas is uniformly deposited on the surface of the substrate S.

The motor housing 319 c is fixed to a bracket 319 d. The bracket 319 dis connected to the elevation rod 319 e connected to a lower portion ofthe lower chamber 312 b and elevated along the elevation rod 319 e. Thebracket 319 c is screw-coupled to a lower rod 419, and the lower rod 419is rotated by the elevation motor 319 a. That is, the lower rod 419 isrotated as the elevation motor 319 a is rotated. Thus, the bracket 319 dand the motor housing 319 c may be elevated together. Therefore, therotation shaft 318 and the substrate holder 328 may be elevatedtogether. The substrate holder 328 may be moved from the stackingposition into the process position by the elevation motor 319 a. Abellows 318 a connects the lower chamber 312 b to the motor housing 319c. Thus, the inside of the lower chamber 312 b may be sealed. FIG. 14 isa view illustrating a state in which the substrate holder of FIG. 1 ismoved into a process position.

Referring to FIGS. 15 and 16, the heat-shield plate 316 is disposedunder the substrate holder 328. As the rotation shaft 318 is elevated,the substrate holder 328 is elevated together with the rotation shaft318. The heat-shield plate 316 closes the opened lower side of theinternal reaction tube 314 to prevent heat within the internal reactiontube 314 from being transmitted into the stacking space within the lowerchamber 312 b.

According to the embodiment, the stacking space and the exhaust spacemay be effectively exhausted to prevent the reaction gas from beingdeposited within the lower chamber.

Although the present invention is described in detail with reference tothe exemplary embodiments, the invention may be embodied in manydifferent forms. Thus, technical idea and scope of claims set forthbelow are not limited to the preferred embodiments.

What is claimed is:
 1. A substrate processing apparatus in whichprocesses with respect to substrates are performed, the substrateprocessing apparatus comprising: a lower chamber having an opened upperside, the lower chamber comprising a passage allowing the substrates topass therethrough in a side thereof; an external reaction tube closingthe opened upper side of the lower chamber to provide a process space inwhich the processes are performed; an internal reaction tube disposedwithin the external reaction tube, the internal reaction tube beingdisposed around a substrate holder placed in a process position todefine a reaction region with respect to the substrates; a heaterdisposed outside the external reaction tube to heat the process space;the substrate holder being configured to support one or more substratesvertically stacked, the substrate holder being movable between astacking position in which the substrates are stacked and a processposition in which the processes with respect to the substrates areperformed; a heat-shield plate disposed under the substrate holder toclose an opened lower side of the internal reaction tube when thesubstrate holder is disposed at the process position; a plurality ofsupply nozzles disposed along an inner wall of the external reactiontube and having respective supply holes to discharge reaction gastherethrough; and a plurality of exhaust nozzles disposed along theinner wall of the external reaction tube and having respective exhaustholes to draw unreacted gas and byproducts out of the process space,wherein the supply holes are disposed along a circumferential directionof an inner wall of the internal reaction tube to have a phasedifference, disposed at heights different from each other and positionedwithin the internal reaction tube, the exhaust holes are disposed alongthe circumferential direction of the inner wall of the internal reactiontube to have a phase difference, disposed at heights different from eachother and positioned within the internal reaction tube, and each of thesupply holes faces a corresponding one of the exhaust holes which isdisposed at the same height with that of said each of the supply holesacross a central axis of the internal reaction tube.
 2. The substrateprocessing apparatus of claim 1, wherein the substrate holder isdisposed within a stacking space at the stacking position and disposedwithin the process space at the process position.
 3. The substrateprocessing apparatus of claim 1, further comprising a rotation shaftconnected to the substrate holder, the rotation shaft being rotated in apreset direction during the processes, wherein the heat-shield plate isdisposed on the rotation shaft.
 4. The substrate processing apparatus ofclaim 1, wherein the heat-shield plate is formed of one of ceramic,quartz, a metal material coated with ceramic, AlN, Ni, and Ni—Cr alloy.